JPH05342524A - Magnetic head and its production - Google Patents

Abstract

PURPOSE:To provide the magnetic head in which magnetic metallic thin films having a high saturation magnetic flux density is disposed near its magnetic gap and which sufficiently suppresses the reaction of welding glass and the metal magnetic thin films contg. nitrogen and does not exert any adverse influence on magnetic recording characteristics and the process for production thereof. CONSTITUTION:The metal magnetic thin films are constituted of magnetic materials which contain nitride in the first layers 9a, 9b on magnetic core half bodies 8a, 8b side consisting of ferrite and do not contain the nitrogen in the second layers 10a, 10b on welding glass 12a, 12b side. The magnetic core half bodies are subjected to a heating treatment after the deposition of the first metal thin films, by that, the diffusion of the first metal thin films and the second metal thin films at the time of welding is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head which slides a magnetic core on a magnetic recording medium to perform magnetic recording or reproduction, and particularly, the magnetic core is mainly made of ferrite,
The present invention relates to a magnetic head in which a metal magnetic thin film having a high saturation magnetic flux density is arranged near the magnetic gap.

[0002]

2. Description of the Related Art In recent years, in devices such as VTRs (video tape recorders) and DATs (digital audio tape recorders), magnetic recording media having a high coercive force have been used in order to increase the density of magnetic recording. As a result, as a magnetic head, a magnetic thin film of high saturation magnetic flux density such as send or amorphous was formed and deposited by a vacuum thin film forming method on the abutting surface facing the magnetic gap of a magnetic core formed mainly of ferrite. Magnetic head, so-called MIG
(Metal in gap) heads have come to be used.

FIG. 7 is a diagram showing an example of the configuration of this type of MIG head. In FIG. 1b is a magnetic core half made of ferrite, 3 is a winding window, 4a and 4b are sendust thin films, 5 is a winding groove, 6 is welding glass, 7 is a magnetic recording medium sliding surface, and g is a magnetic gap. is there.

On the other hand, it has been proposed to use a magnetic thin film containing nitrogen as the above-mentioned magnetic thin film in order to further improve the magnetic characteristics and wear resistance.

As a method for incorporating nitrogen into the magnetic thin film, it is general to form the magnetic thin film by a reactive sputtering method using a sputtering gas containing argon (Ar) and nitrogen (N). Is.

[0006]

However, in the case of a thin film containing nitrogen, the reaction with the fused glass is vigorous, and in particular Fe--
In the case of an Al-Si-based sendust thin film, the addition of N ₂ causes the reactivity to rapidly increase, resulting in bubbles.

The air bubbles are also generated in a portion in sliding contact with the magnetic recording medium, which damages the magnetic recording medium and causes a large amount of magnetic components of the magnetic head to adhere due to the separation of the magnetic components, which causes dropout and the like. It was Due to these causes, the defect rate is generally high in the MIG head using the metal magnetic thin film containing nitrogen.

The reason why the nitrogen-containing metal magnetic thin film has a strong reactivity with the fused glass has not been completely clarified at present, but it is considered as follows.

That is, when the sendust film is taken as an example, N
_{When 2} is included, a safe passive film is unlikely to be formed like a general sendust film, and is easily oxidized deeply.
Therefore, it is considered that bubbles may be generated at the boundary with the fused glass because the magnetic film takes in oxygen in the glass.

As measures against this, firstly, a fused glass which does not react may be selected, and secondly, a reaction preventive film may be provided to increase the film thickness.

However, in the case of a nitrogen-containing sendust film, the reaction is so vigorous that it is virtually impossible to select a fused glass that does not react.

If a metal thin film or a ceramic thin film is formed thick as the reaction preventing film, the reaction can be prevented. In particular, the Cr ₂ O ₃ or Cr film does not melt in glass,
It is most suitable as a protective film, but Cr ₂ O ₃ and Cr
The film has very good wear resistance with respect to the magnetic recording medium, and does not wear as compared with the fused glass and the SiO ₂ film of the gap material, and thus becomes a convex portion on the sliding surface of the magnetic recording medium.
Therefore, the protrusion may damage the magnetic recording medium.

In particular, when the protective film at the boundary between the fused glass and the magnetic thin film is also used as the non-magnetic film for the magnetic gap, a convex portion is formed in the magnetic gap portion, and the magnetic recording medium is peeled off. The peeled magnetic powder adheres to the magnetic gap, which is a fatal defect.

Therefore, the thickness of the protective film can be only about 100 Å, and it has been impossible to sufficiently suppress the reaction between the fused glass and the magnetic thin film.

Under the above circumstances, the present invention is a magnetic head in which a magnetic core is mainly made of ferrite and a metal magnetic thin film having a high saturation magnetic flux density is arranged in the vicinity of a magnetic gap, and a metal magnetic thin film containing fused glass and nitrogen. It is an object of the present invention to provide a magnetic head that sufficiently suppresses the reaction with the magnetic recording medium and does not have any adverse effect on the magnetic recording characteristics, and a manufacturing method thereof.

[0016]

[Means for Solving the Problems] Under such a purpose,
In the magnetic head of the present invention, a metal magnetic thin film is deposited on at least one of a pair of magnetic core halves made of ferrite, and the pair of magnetic core halves is made of fused glass via the metal magnetic thin film and the magnetic gap. In the bonded magnetic head, the metal magnetic thin film is composed of a magnetic material in which the first layer on the ferrite side contains nitrogen and the second layer on the fused glass side does not contain nitrogen.

Further, in the method of manufacturing a magnetic head according to the present invention, a first metal magnetic thin film containing nitrogen is deposited on at least one of a pair of magnetic core halves made of ferrite, and the first metal thin film of the first metal thin film is formed. The deposited magnetic core half is heat-treated, and after the heat treatment, a nitrogen-free second metallic magnetic thin film is deposited on the first metallic magnetic thin film, and then the second metallic magnetic thin film is coated. After the bonding, the pair of magnetic core halves are bonded by the fused glass via the first and second metal magnetic thin films and the magnetic gap.

[0018]

According to the structure of the magnetic head as described above, the reaction between the nitrogen-containing magnetic thin film and the fused glass can be suppressed without providing a thick reaction preventive film between the fused glass and the magnetic thin film.

Further, after the deposition of the first metal thin film, the magnetic core half body is once subjected to heat treatment to prevent diffusion between the first metal thin film and the second metal thin film during welding, The effect of suppressing the reaction between the magnetic thin film and the fused glass can be further enhanced.

[0020]

FIG. 1 is a view of a magnetic head according to an embodiment of the present invention as seen from a sliding surface of a magnetic recording medium, and FIG. 2 is an enlarged view of a main part thereof.

In the figure, 8a and 8b are magnetic core halves made of ferrite, respectively, and sendust thin films 9a and 9b containing nitrogen are deposited on the end faces of these magnetic core halves.
Then, the sendust thin films 9a and 9b containing nitrogen.
Above the sendust thin film 10a containing no nitrogen,
10b is deposited as a magnetic protective film.

Reference numerals 11a and 11b are reaction preventing films having a thickness of about 100Å. 12a and 12b are welded glasses, respectively, and the reaction preventive films 11a and 11b are interposed between the welded glasses 12a and 12b and the sendust thin films 10a and 10b containing no nitrogen.

In the magnetic head of this embodiment, the thickness of the protective magnetic thin films 10a and 10b is 100 Å or more and 1 μm or less. The reason for this will be described below.

That is, when the thickness of the protective magnetic thin films 10a and 10b is 100Å, the temperature at the time of glass welding is 500 ° C.
At about 600 ° C., diffusion occurs between the first layer of nitrogen-containing sendust thin films 9a and 9b and the second layer of nitrogen-free protective sendust thin films 10a and 10;
₂ also moves to the protective magnetic thin films 10a and 10b, which increases the possibility that large glass bubbles as described above are generated on the sliding surface of the magnetic recording medium.

On the other hand, the protective magnetic thin films 10a, 10
If the thickness of b is 1 μm or more, the following problems may remain.

That is, one is that the characteristics of the sendust film containing nitrogen, which is used for improving the characteristics in the high frequency range, cannot be sufficiently extracted as the characteristics of the magnetic head itself.

Further, a sendust film 9a containing nitrogen,
The hardness of 9b is about 900 to 1000 (H _V ), and the hardness of the sendust films 10a and 10b containing no nitrogen is 5%.
00 to 700 (H _V) is about the thickness of the sendust film not containing nitrogen becomes a more 1 [mu] m, level difference occurs between the two layers, it can cause damage to the magnetic recording medium is there. It has been confirmed that when the thickness of the sendust film containing no nitrogen is 1 μm or less, it is supported by the sendust films 9a and 9b containing nitrogen and the step is almost eliminated.

As the reaction preventing films 11a and 11b, the above-mentioned Cr ₂ O ₃ film or Cr film is used.

Next, a method of manufacturing the magnetic head shown in FIGS. 1 and 2 will be described with reference to FIGS. 3 (A) to 3 (F).

First, as shown in FIG. 3A, the ferrite plate 15 is processed. This is a step of forming the track groove 13 and the winding groove 14 in consideration of film formation in a later step.

Next, as shown in FIG. 3B, as the first magnetic thin film 16, a magnetic thin film 16 made of Fe 85 wt% (weight percent), Al ₄ wt%, Si 9 wt%, N ₂ 2 wt% is 5 μm. Put on. Here, sendust containing nitrogen was formed by performing reactive sputtering in a gas obtained by adding nitrogen to ar.

Immediately after the sputtering, the piece shown in FIG. 3 (B) is bent back toward the magnetic thin film 16 of the first layer. That is, -5 to -10 x 10 ⁹ (dyn / cm ² )
Very large stress is generated. If this is left as it is, the accuracy of the gap length cannot be obtained in the subsequent butting step, so post-annealing for stress relief is performed at about 400 ° C to 450 ° C.

By the heat treatment at this time, the strength of (110) is increased, the orientation is increased, and the crystallite is increased. This state is shown in FIGS. FIG. 4 shows the first-layer magnetic thin film 1.
6 X-ray diffraction result immediately after sputtering, FIG.
The results of X-ray diffraction after heat treatment at 00 ° C to 450 ° C for 2 hours are shown.

This is because the first-layer magnetic thin film 16 deposited in the step shown in FIG. 3B is rearranged by heat treatment,
This indicates that atomic level migration is occurring. Even when a magnetic thin film containing no nitrogen is formed on the magnetic thin film of the first layer by stopping addition of N ₂ during the formation of the magnetic thin film 16 of the first layer, as described above. At the time of heat treatment for stress removal and glass welding, movement at the atomic level is activated in the film, and nitrogen diffuses into the magnetic thin film containing no nitrogen.

In the present embodiment, in order to prevent the effect of providing the magnetic thin film containing no nitrogen as the protective film from being deteriorated due to the generation of bubbles accompanying this, the first nitrogen containing film is formed.
After forming the magnetic thin film 16 of the layer, after performing heat treatment for stress relief to rearrange the atoms in the film,
Nitrogen-free magnetic thin film 1 as second protective film
7 was applied.

Here, the above-mentioned stress relief heat treatment is performed at 400 ° C.
By performing the heating at ˜450 ° C., the temperature is close to the subsequent glass welding temperature of about 550 ° C., so that diffusion does not easily occur during this glass welding. FIG. 6 shows the X-ray diffraction result after heat treatment at about 550 ° C. for 2 hours.

As is apparent from FIGS. 5 and 6, 400.degree.
After the stress relief heat treatment at 450 ° C, the diffraction result is about 55
It is almost the same as the diffraction result after the heat treatment at 0 ° C. for 2 hours, and it can be seen that the atomic arrangement is hardly changed.

After the stress relieving heat treatment at 400 ° C. to 450 ° C., the nitrogen-free magnetic thin film 17 as a protective film is deposited as shown in FIG.
In the step shown in (D), a thin film 18 made of a gap material that serves as a magnetic gap and the above-described reaction preventive film is deposited on the second magnetic thin film 17.

After that, as shown in FIG. 3 (E), each piece is cut into a size convenient for welding, and as shown in FIG.
The low melting point glass 19 is welded for 2 hours at 50 ° C., and the head is cut along the lines A and B of FIG. 3 (F) to obtain the head of this embodiment shown in FIGS.

By adding a small amount of Ru, for example, 0.05 wt% to the magnetic films 16 and 17, the reactivity with the fused glass is further reduced, and the effect of the present invention can be further enhanced.

[0041]

As described above, according to the magnetic head of the present invention, in the magnetic head in which the magnetic core is mainly made of ferrite and the metal magnetic thin film having a high saturation magnetic flux density is arranged in the vicinity of the magnetic gap, By constituting the thin film from a magnetic material in which the first layer on the ferrite side contains nitrogen and the second layer on the fused glass side does not contain nitrogen, the reaction between the fused glass and the metallic magnetic thin film containing nitrogen is sufficiently performed. Suppress and
It is possible to obtain a magnetic head that does not adversely affect the magnetic recording characteristics.

Further, according to the method of manufacturing a magnetic head of the present invention, the magnetic core half having the first metal thin film adhered thereto is heat-treated, and after the heat treatment, the second metal magnetic thin film containing no nitrogen. Is deposited on the first metal magnetic thin film to prevent diffusion between the first metal thin film and the second metal thin film during welding, and to suppress the reaction between the magnetic thin film and the fused glass. It can be further increased.

[Brief description of drawings]

FIG. 1 is a diagram of a magnetic head according to an embodiment of the present invention as viewed from a sliding surface of a magnetic recording medium.

FIG. 2 is an enlarged view of a main part of the magnetic head shown in FIG.

FIG. 3 is a diagram showing a manufacturing process of the magnetic head shown in FIGS. 1 and 2;

FIG. 4 is a diagram showing an X-ray diffraction result immediately after sputtering of the magnetic thin film of the first layer in the manufacturing process of FIG. 3;

FIG. 5 is a diagram showing an X-ray diffraction result after heat treatment at 400 ° C. to 450 ° C. for 2 hours in the manufacturing process of FIG.

FIG. 6 is a schematic diagram of the 550 for glass welding during the manufacturing process of FIG.
It is a figure which shows the X-ray-diffraction result after heat-processing at 2 degreeC for 2 hours.

FIG. 7 is a perspective view showing a configuration example of a conventional magnetic head.

[Explanation of symbols]

8a, 8b Magnetic core half body composed of ferrite core 9a, 9b Sendust thin film containing nitrogen (first layer) 10a, 10b Sendust thin film containing no nitrogen (second layer) 11a, 11b Anti-reaction film 12a, 12b Welded glass 15 Ferrite Plate 16 First-Layer Metal Magnetic Thin Film 17 Second-Layer Metal Magnetic Thin Film 19 Low Melting Point (Fused) Glass

Claims (7)

[Claims] 1. A metal magnetic thin film is deposited on at least one of a pair of magnetic core halves made of ferrite, and the pair of magnetic core halves are bonded by means of fused glass via the metal magnetic thin film and a magnetic gap. The magnetic head according to claim 1, wherein the metal magnetic thin film has a ferrite-side first layer containing nitrogen and a fused glass-side second layer containing no nitrogen. 2. The second layer of the metal magnetic thin film is Fe--Al.
The magnetic head according to claim 1, wherein the magnetic head has a composition containing -Si as a main component. 3. The first layer of the metallic magnetic thin film is also Fe--
The magnetic head according to claim 2, wherein the magnetic head has a composition containing Al-Si as a main component. 4. The Ru is added to each of the first layer and the second layer of the metal magnetic thin film.
Magnetic head. 5. The thickness of the first layer of the metal magnetic thin film is 1
2. The thickness is from 00Å to 1 μm.
Magnetic head. 6. The magnetic head according to claim 1, wherein the metal magnetic thin film, the fused glass, and a protective film are formed, and a part of the protective film constitutes the magnetic gap. 7. A first metal magnetic thin film containing nitrogen is applied to at least one of a pair of magnetic core halves made of ferrite, and the magnetic core halves to which the first metal thin film is applied are heat-treated. The second metal magnetic thin film containing no nitrogen after the heat treatment is
After depositing on the first metal magnetic thin film, and then depositing the second metal magnetic thin film, the pair of magnetic core halves are attached to the first and second metal magnetic thin films and the magnetic gap by means of fused glass. A method of manufacturing a magnetic head, characterized in that the magnetic heads are bonded to each other.